Gal谩pagos birds expand their eating habits
A new ecological concept called 鈥渋nteraction release鈥� explains how certain island birds developed a taste for flowers.
A frigate takes to the sky above San Crist贸bal Island in 2001. Scientists have for the first time discovered a general shift in diets across an entire group of animals while studying birds on the Galapagos islands that once helped inspire Charles Darwin's theory of evolution. The Spanish-led team observed 19 of the 23 species of Galapagos land birds visiting flowers to eat nectar and pollen, apparently because their preferred foods of seeds or insects are in short supply on the remote Pacific islands.
Reuters/File
Hunger has a funny way of making otherwise picky eaters a little more adventurous.
On the Gal谩pagos Islands, where plant and insect diversity is low, virtually every land bird has expanded its diet to include flowers and nectar. And while that might be good news for the birds, it could have potentially negative after-effects for the island environment. According to published today in Nature Communications, the phenomenon is unprecedented.
A research group led by Anna Traveset, of the Institut Mediterrani d鈥橢studis Avan莽ats (IMEDEA), observed the feeding habits of 19 Gal谩pagos bird species. Over time, the team carefully mapped out each species鈥� interactions with over 100 plant species on the archipelago.
Dr. Traveset and her team found that nearly every species of land bird on the entire archipelago had expanded its diet to include flowers and nectar. They recorded 421 bird-plant network connections on the archipelago 鈥� 20 times that of previous estimations. It was an ecological anomaly 鈥� island species widening their feeding niche to compensate for food scarcity, thus interacting with more native species than their mainland relatives.
鈥淎t present, we expect it to be a general oceanic island phenomenon, but no comparable data are yet available,鈥� Traveset wrote in the study.
This phenomenon has been reported for single species, but never before for an entire ecological community. As such, Traveset鈥檚 team was tasked with coming up with a name for the phenomenon 鈥� they settled on 鈥渋nteraction release,鈥� a subconcept of 鈥渆cological release.鈥� The latter occurs when species introduced to foreign environments either establish a local population or die out.
Obviously, generalized feeding habits benefit the birds of the Gal谩pagos 鈥� survival is the ultimate ideal for any species. But the environmental impacts of this phenomenon remain to be seen.
鈥淚nteraction release is crucial to the survival of native birds but simultaneously threatens the unique biodiversity of this archipelago,鈥� the study reads, 鈥渁s the birds also visit invading plants, likely facilitating their integration into pristine native communities.鈥�